CT-guided percutaneous administration of Spot sterile carbon stain to a single F-18 FDG positive mesenteric lymph node to allow identification during subsequent laparoscopic resection

Purpose: To evaluate the feasibility and efficacy of CT-guided percutaneous administration and off-label use of Spot sterile carbon stain (GI Supply, Camp Hill, PA) to a single PET-positive mesenteric lymph node to allow identification during subsequent laparoscopic resection.

Methods: An asymptomatic 61-year-old male veteran with past medical history only for benign prostatic hyperplasia presented with a mildly elevated PSA. A screening CT demonstrated a 2.3 × 0.8 cm mesenteric mass and findings resembling mesenteric panniculitis; however, following PET revealed F-18 FDG avidity, and a neoplastic process could not be entirely excluded. An initial attempt at percutaneous biopsy was non-diagnostic. Therefore, a second percutaneous intervention with localization and off-label administration of Spot dye was performed to aid in subsequent laparoscopic resection.

Results: The Spot dye was identified during laparoscopy and the PET-positive mesenteric mass was successfully resected. Histology diagnosed the non-malignant etiology of organizing hematoma. A follow-up PET/CT confirmed interval resection of the previous PET-avid mass.

Conclusions: This case report is the first to describe the off-label administration and use of Spot dye by a CT-guided percutaneous technique, allowing improved visualization during subsequent laparoscopic resection. Spot is composed of sterile, carbon-based particles which leave a permanent tattoo and is FDA-approved for the inking of the Gastrointestinal tract. Interventional radiologists should consider the off-label use of Spot dye in marking regions of interest as it safely provides a permanent tattoo which may aid in future identification.